This invention relates to an ultrasonic generator driven to assume a reinforced radial resonant mode and more particularly to such an ultrasonic generator for use in controlled atomization of liquids.
The manner in which structural members of various configurations assume modes of flexural vibration resonance is treated in some detail in U.S. Pat. No. 3,804,329 issued to the applicant herein. As disclosed therein lack of investigative apparatus and analytical techniques has been severely limiting in the design of vibrating systems which are capable of reaching sufficiently large magnitudes of resonance at sufficiently high frequencies over sufficiently large areas to provide for atomization of liquids at useful flow rates. Therefore atomization of liquids such as fuels for subsequent combustion, while consuming acceptably smaller power levels in obtaining the resonant modes in the vibratory atomizer has posed severe technical problems. Moreover, there has been a need to devise resonant vibrating structure which conform to the convenient shapes for use in devices such as carburetors, burners, and so forth which are used to process fuels prior to ignition so that efficient burning and reduction of pollutants is promoted. In the '329 patent, at column 14, relation D, the term h is present. This is the thickness of the disc discussed. In column 13, lines 19 through 25, it is stated that the equations (a) to (m) therein are general, and that they may be more conveniently expressed in other than polar coordinates for plate or tubular resonators. In the relationships 14 and 15 recited hereafter in this disclosure, the cylindrical radius is the only tube dimension present in the expression for the radial resonant frequency and the cylinder length is the only tube dimension present in the expression for the axial resonant frequency expression. Thus, the distinction between the two approaches for obtaining resonant atomizing members is apparent.
It is apparent that an efficient, conveniently shaped high resonant amplitude resonator with predicitable resonating characteristics is needed for use in liquid atomization and emulsion formation applications.